1. Field of the Invention
The present invention relates to a hot water supply system in which two hot water supply apparatuses are communicatively connected together to cooperatively perform a hot water supply operation.
2. Description of the Related Art
Hot water supply systems have been known which provide improved hot water supply capabilities by communicatively connecting a plurality of hot water supply apparatuses to a connection unit that allows the plurality of hot water supply apparatuses to cooperatively supply hot water; a water supply pipe and a hot water supply pipe are connected in parallel to each of the plurality of hot water supply apparatuses (see, for example, Japanese Patent Laid-Open No. 2002-357361).
In a known hot water supply system in which two hot water supply apparatuses cooperatively supply hot water, a controller in each of the hot water supply apparatuses provides a function for controlling a cooperative operation. The two hot water supply systems are directly connected together via a communication cable so that one of the hot water supply apparatuses operates as a master, while the other operates as a slave (see, for example, Japanese Patent Laid-Open No. 2003-222399). This hot water supply system eliminates the need for a connection unit, thus enabling a reduction in the cost of and the installation space for the connection unit.
In the above system, the controller in each of the hot water supply apparatuses provides a function for controlling a cooperative operation to allow the two hot water supply apparatuses to perform the cooperative operation. Then, when the controller provided in one of the hot water supply apparatuses fails and can no longer control the cooperative operation, the failing controller needs to be replaced with a new one. Before a new controller for replacement is available, the normal hot water supply apparatus can independently perform a hot water supply operation. Thus, disadvantageously, the level of the hot water supply capability of the hot water supply system decreases to half.
An object of the present invention is to eliminate this disadvantage to provide a hot water supply system which allows two hot water supply apparatuses to operate cooperatively to supply hot water and which can avoid degrading a hot water supply capability when one of the two hot water supply apparatuses cannot perform as a master or slave.